Multi-chip packaging of silicon photonics

Abstract

A multi-chip package assembly includes a substrate, a first semiconductor chip attached to the substrate, and a second semiconductor chip attached to the substrate, such that a portion of the second semiconductor chip overhangs an edge of the substrate. A first v-groove array for receiving a plurality of optical fibers is present within the portion of the second semiconductor chip that overhangs the edge of the substrate. An optical fiber assembly including the plurality of optical fibers is positioned and secured within the first v-groove array of the second semiconductor chip. The optical fiber assembly includes a second v-groove array configured to align the plurality of optical fibers to the first v-groove array of the second semiconductor chip. An end of each of the plurality of optical fibers is exposed for optical coupling within an optical fiber connector located at a distal end of the optical fiber assembly.

What is claimed is: 
     
       1. A multi-chip package assembly, comprising:
 a substrate; 
 a first semiconductor chip attached to the substrate; 
 a second semiconductor chip attached to the substrate such that a portion of the second semiconductor chip overhangs an edge of the substrate, wherein a first v-groove array for receiving a plurality of optical fibers is present within the portion of the second semiconductor chip that overhangs the edge of the substrate; and 
 an optical fiber assembly including the plurality of optical fibers positioned and secured within the first v-groove array of the second semiconductor chip, the optical fiber assembly including a second v-groove array configured to align the plurality of optical fibers to the first v-groove array of the second semiconductor chip, wherein an end of each of the plurality of optical fibers is exposed for optical coupling within an optical fiber connector of the optical fiber assembly, the optical fiber connector located at a distal end of the optical fiber assembly relative to the second semiconductor chip. 
 
     
     
       2. The multi-chip package assembly as recited in  claim 1 , wherein the substrate includes a lateral extension portion that extends outward from the central region of the substrate next to the portion of the second semiconductor chip that overhangs the edge of the substrate and next to the second v-groove array of the optical fiber assembly. 
     
     
       3. The multi-chip package assembly as recited in  claim 1 , wherein the first semiconductor chip is a system-on-chip, and wherein the second semiconductor chip is a photonic device chip. 
     
     
       4. The multi-chip package assembly as recited in  claim 1 , wherein the first semiconductor chip does not overhang any edge of the substrate. 
     
     
       5. The multi-chip package assembly as recited in  claim 1 , wherein the first semiconductor chip is flip-chip connected to the substrate, and wherein the second semiconductor chip is flip-chip connected to the substrate. 
     
     
       6. The multi-chip package assembly as recited in  claim 1 , wherein the second semiconductor chip includes a dam structure positioned within the portion of the second semiconductor chip that overhangs the edge of the substrate, the dam structure configured to extend along the edge of the substrate such that gap exists between the dam structure and the edge of the substrate. 
     
     
       7. The multi-chip package assembly as recited in  claim 6 , further comprising:
 an underfill material disposed between the second semiconductor chip and the substrate, the dam structure separating the underfill material from the first v-groove array of the second semiconductor chip. 
 
     
     
       8. The multi-chip package assembly as recited in  claim 1 , further comprising:
 an optical adhesive disposed over the plurality of optical fibers within the first v-groove array of the second semiconductor chip. 
 
     
     
       9. The multi-chip package assembly as recited in  claim 1 , wherein the optical fiber assembly includes a cover structure secured to the second v-groove array of the optical fiber assembly, the cover structure shaped and positioned to extend over and secure the plurality of optical fibers within the second v-groove array of the optical fiber assembly. 
     
     
       10. The multi-chip package assembly as recited in  claim 9 , wherein the cover structure is secured to the second v-groove array of the optical fiber assembly by an epoxy. 
     
     
       11. The multi-chip package assembly as recited in  claim 1 , further comprising:
 a stiffener structure attached to both the second semiconductor chip and the second v-groove array of the optical fiber assembly. 
 
     
     
       12. The multi-chip package assembly as recited in  claim 11 , wherein the stiffener structure is configured to substantially cover a top surface of the second semiconductor chip and the second v-groove array of the optical fiber assembly, wherein the top surface of the second semiconductor chip faces away from the substrate. 
     
     
       13. The multi-chip package assembly as recited in  claim 1 , further comprising:
 an integrated heat spreader attached to the substrate such that the first semiconductor chip and the second semiconductor chip are located between the integrated heat spreader and the substrate, the integrated heat spreader sized and shaped to cover both the first semiconductor chip and the second semiconductor chip. 
 
     
     
       14. The multi-chip package assembly as recited in  claim 13 , wherein the integrated heat spreader is sized and shaped to substantially cover an entirety of a top surface of the substrate. 
     
     
       15. The multi-chip package assembly as recited in  claim 13 , further comprising:
 a thermal interface material disposed between the integrated heat spreader and both of the first semiconductor chip and the second semiconductor chip. 
 
     
     
       16. The multi-chip package assembly as recited in  claim 1 , wherein the optical fiber assembly is a first optical fiber assembly, and wherein the plurality of optical fibers is a first plurality of optical fibers, and wherein the optical fiber connector is a first optical fiber connector, the multi-chip package assembly further comprising:
 a third semiconductor chip attached to the substrate such that a portion of the third semiconductor chip overhangs an edge of the substrate, wherein a third v-groove array for receiving a second plurality of optical fibers is present within the portion of the third semiconductor chip that overhangs the edge of the substrate; and 
 a second optical fiber assembly including the second plurality of optical fibers positioned and secured within the third v-groove array of the third semiconductor chip, the second optical fiber assembly including a fourth v-groove array configured to align the second plurality of optical fibers to the third v-groove array of the third semiconductor chip, wherein an end of each optical fiber of the second plurality of optical fibers is exposed for optical coupling within a second optical fiber connector of the second optical fiber assembly, the second optical fiber connector located at a distal end of the second optical fiber assembly relative to the third semiconductor chip. 
 
     
     
       17. The multi-chip package assembly as recited in  claim 16 , wherein the third semiconductor chip is positioned adjacent to the second semiconductor chip. 
     
     
       18. The multi-chip package assembly as recited in  claim 16 , wherein the portion of the second semiconductor chip and the portion of the third semiconductor chip overhang a same edge of the substrate. 
     
     
       19. The multi-chip package assembly as recited in  claim 16 , wherein the portion of the second semiconductor chip and the portion of the third semiconductor chip overhang different edges of the substrate. 
     
     
       20. The multi-chip package assembly as recited in  claim 16 , further comprising:
 a fourth semiconductor chip attached to the substrate such that a portion of the fourth semiconductor chip overhangs an edge of the substrate, wherein a fifth v-groove array for receiving a third plurality of optical fibers is present within the portion of the fourth semiconductor chip that overhangs the edge of the substrate; and 
 a third optical fiber assembly including the third plurality of optical fibers positioned and secured within the fifth v-groove array of the fourth semiconductor chip, the third optical fiber assembly including a sixth v-groove array configured to align the third plurality of optical fibers to the fifth v-groove array of the fourth semiconductor chip, wherein an end of each optical fiber of the third plurality of optical fibers is exposed for optical coupling within a third optical fiber connector of the third optical fiber assembly, the third optical fiber connector located at a distal end of the third optical fiber assembly relative to the fourth semiconductor chip. 
 
     
     
       21. The multi-chip package assembly as recited in  claim 20 , wherein the third semiconductor chip is positioned adjacent to the second semiconductor chip, and wherein the portion of the second semiconductor chip and the portion of the third semiconductor chip overhang a first edge of the substrate, and wherein the portion of the fourth semiconductor chip overhangs a second edge of the substrate that is different from the first edge of the substrate. 
     
     
       22. The multi-chip package assembly as recited in  claim 21 , wherein the first edge of the substrate and the second edge of the substrate are on opposite sides of the substrate. 
     
     
       23. The multi-chip package assembly as recited in  claim 20 , further comprising:
 a fifth semiconductor chip attached to the substrate such that a portion of the fifth semiconductor chip overhangs an edge of the substrate, wherein a seventh v-groove array for receiving a fourth plurality of optical fibers is present within the portion of the fifth semiconductor chip that overhangs the edge of the substrate; and 
 a fourth optical fiber assembly including the fourth plurality of optical fibers positioned and secured within the seventh v-groove array of the fifth semiconductor chip, the fourth optical fiber assembly including an eighth v-groove array configured to align the fourth plurality of optical fibers to the seventh v-groove array of the fifth semiconductor chip, wherein an end of each optical fiber of the fourth plurality of optical fibers is exposed for optical coupling within a fourth optical fiber connector of the fourth optical fiber assembly, the fourth optical fiber connector located at a distal end of the fourth optical fiber assembly relative to the fifth semiconductor chip. 
 
     
     
       24. The multi-chip package assembly as recited in  claim 23 , wherein the third semiconductor chip is positioned adjacent to the second semiconductor chip, wherein the portion of the second semiconductor chip and the portion of the third semiconductor chip overhang a first edge of the substrate, wherein the fourth semiconductor chip is positioned adjacent to the fifth semiconductor chip, and wherein the portion of the fourth semiconductor chip and the portion of the fifth semiconductor chip overhang a second edge of the substrate that is different from the first edge of the substrate. 
     
     
       25. The multi-chip package assembly as recited in  claim 24 , wherein the first edge of the substrate and the second edge of the substrate are on opposite sides of the substrate. 
     
     
       26. A method for manufacturing a multi-chip package assembly, comprising:
 having a substrate; 
 attaching a first semiconductor chip to the substrate; 
 attaching a second semiconductor chip to the substrate such that a portion of the second semiconductor chip overhangs an edge of the substrate, wherein a first v-groove array for receiving a plurality of optical fibers is present within the portion of the second semiconductor chip that overhangs the edge of the substrate; and 
 attaching an optical fiber assembly to the second semiconductor chip by positioning and securing the plurality of optical fibers of the optical fiber assembly within the first v-groove array of the second semiconductor chip, wherein an end of each of the plurality of optical fibers is exposed for optical coupling within an optical fiber connector of the optical fiber assembly, the optical fiber connector located at a distal end of the optical fiber assembly relative to the second semiconductor chip. 
 
     
     
       27. The method as recited in  claim 26 , further comprising:
 disposing an underfill material between the second semiconductor chip and the substrate, with a dam structure of the second semiconductor chip preventing the underfill material from being disposed over the first v-groove array of the second semiconductor chip. 
 
     
     
       28. The method as recited in  claim 26 , further comprising:
 securing a cover structure to the second v-groove array of the optical fiber assembly, such that the cover structure extends over and secures the plurality of optical fibers within the second v-groove array of the optical fiber assembly. 
 
     
     
       29. The method as recited in  claim 26 , further comprising:
 attaching both the second semiconductor chip and the second v-groove array of the optical fiber assembly to a stiffener structure before attaching the second semiconductor chip to the substrate. 
 
     
     
       30. The method as recited in  claim 26 , further comprising:
 attaching an integrated heat spreader to the substrate such that the first semiconductor chip and the second semiconductor chip are located between the integrated heat spreader and the substrate.